It has been recently discovered that by submitting certain cadmium sulfide semiconducting compositions to a "pressure quenching treatment", wherein the composition is compressed under a high pressure of 40K bars or higher and the pressure is suddenly released at rates in excess of 10.sup.4 bars/sec. at room temperature, the composition is transformed into a new metastable state, which possesses different mechanical, optical, electrical and magnetic properties than those of the starting composition. The product thus obtained is black in color, contains a lenticular platelet structure, has a structural morphology containing some retained NaCl phase, possesses an increased electrical conductivity by approximately four orders of magnitude, and exhibits both strong negative (diamagnetic) and positive (paramagnetic) magnetism, which varies with the applied magnetic field and other physical treatments (C. G. Homan, D. P. Kendall and R. K. MacCrone, Solid State Communications, 32, 521 (1979); E. Brown, C. G. Homan and R. K. MacCrone, Physical Review Letters, 45, 478 Aug. 11, 1980).
The experiments reported in the cited publications were carried out by pressure quenching commercial samples of cadmium sulfide compositions. It was found that pressure quenched product produced from cadmium sulfide sample obtained from one commercial source showed the aforesaid strong diamagnetic and paramagnetic properties, whereas the pressure quenched product produced from a cadmium sulfide sample from another commercial source showed markedly weaker diamagnetic and paramagnetic properties. Elemental analysis showed that the cadmium sulfide samples from these different commercial sources differed only slightly in content of impurities. Consequently, it was not known what element or combination of elements present as impurities in the cadmium sulfide compositions were critical for the production of a material which on pressure quenching yielded a cadmium sulfide product having the unusual magnetic and electrical conducting properties.
Therefore, it is the principal object of the present invention to produce cadmium sulfide compositions having the aforesaid unusual properties by a process consisting of a chemical precipitation reaction followed by a pressure quenching operation.